KCNH2 Variant P1018T Detail

We estimate the penetrance of LQTS for KCNH2 P1018T is 7%. This variant was found in a total of 1 carriers in 0 papers or gnomAD (version 4), 0 had LQTS. P1018T is present in 1 alleles in gnomAD. We have tested the trafficking efficiency of this variant, 95% of WT with a standard error of 2%; in our analysis we used SE < 20% as 'high quality'. Approximately below 50% of WT is considered PS3 moderate and below 30% is PS3 strong. P1018T has not been functionally characterized. This residue is located in a Non_Hotspot region for LQT2. In silico predictions, functional data (if available), and location in structure are equivalent to observing 0 individuals with LQT2 and 10 unaffected individuals.These data combined with observations of carriers lead us to estimate the LQTS penetrance for KCNQ1 P1018T around 7% (0/11).

In Silico Data

PROVEAN PolyPhen-2 BLAST-PSSM REVEL Penetrance Density (%)
-1.496 0.0 -1 0.581 0
PROVEAN scores less than -2 are considered deleterious. REVEL scores higher than 0.5 or 0.75 are considered likely pathogenic (higher sensitivity with the former cutoff, higher specificity with the latter cutoff). A PolyPhen-2 score of 0.85 or greater is considered likely pathogenic. BLAST-PSSM reflects the evolutionary conservation of residue substitutions, more negative numbers indicate fewer observations of the specific substitution than is expected. Penetrance density is our previously published method to calculate the average LQTS probability density in a shell of residues surrounding a residue of interest (Kroncke et al. 2019).

Reported Carrier Data

PubMed ID Year Carriers Unaffected LQT2 Other Disease
LITERATURE, COHORT, AND GNOMAD: - 1 0 0 -
VARIANT FEATURES ALONE: - 10 10 0 -
Summary totals might not agree with the literature table because of duplicate patients, which were excluded from the total counts. We do not distinguish here between multiple missense codons. Missense variants are combined across degenerate codon substitutions since codon-level data were not consistently available for curation.

P1018T has 31 previously observed neighbors within 15 angstroms

A residue within a folded protein on average has nearest neighbors that fall roughly into two shells: a "nearest" neighbor around 5-6 angstroms and a second shell around 11 angstroms. NOTE: some residues appear multiple times at different distances since the functional KV11.1 channel (protein product of KCNH2/hERG) is a homotetramer and occasionally the same residue from multiple subunits is present within the 15A window. All variants shown in the rightmost column have been observed in at least one individual in the literature or gnomAD.

Neighbor Distance (Angstroms) Variants Observed in Individuals
1018 0 P1018L, P1018A,
1017 4 A1017V, A1017T, A1017S, A1017fsX,
1019 4
1016 5
1020 5
1015 7 C1015Y,
1021 7 S1021N, S1021fsX,
1014 8 R1014fsX, R1014X,
1022 8
1013 8
1023 8 L1023P, L1023Del,
1012 9 L1012fsX,
1024 9
1011 10 E1011K,
1025 10
1010 11
1026 11 P1026R,
1009 11 Y1009X,
1027 11 L1027I,
1008 12
1028 12 S1028Del,
1007 13 R1007H, R1007C,
1029 13 S1029fsX,
1006 13 G1006fsX, G1006V,
1030 13 P1030L, P1030X,
1005 14 R1005fsX, R1005Q,
1031 14 G1031C, G1031fsX, G1031X,
1004 14 S1004I, S1004T,
1032 14 R1032Q, R1032X, R1032W, R1032fsX, R1032P,
1003 15 D1003H, D1003Y,
1033 15 R1033X, R1033fsX, R1033Q, R1033W,